The present invention relates to methods of sanitizing structures, buildings, passenger occupiable vehicles, and other enclosed or enclosable spaces. More particularly, the present invention relates to a system and method for killing and removing insects, dust mites and their allergens, bacteria, viruses, fungi, molds, and volatile organic compounds from such enclosures.
A large number of methods have been developed for killing insects, such as termites, in buildings. The most widely used method is tenting the building, then filling the building with a toxic gas for a period of time sufficient to kill termites or other selected insects. This method is effective for killing termites and other insects. However, this method generally requires 12 hours to be effective, requiring building occupants to move out and businesses to be closed for approximately a three day period to insure proper venting of toxic material and/or gas. Tenting the building with heavy tarpaulins requires workers to walk and arrange the tarpaulins on the roof, often damaging the roof system. Food and medications must be placed in sealed containers or removed. Generally the entire building must be treated, even if the infestation is localized.
Techniques of varying effectiveness have been developed using heated air or very cold air to kill termites and other organisms. Typical of these are the methods disclosed by Charles Forbes in U.S. Pat. No. 4,817,329, and Hedman et al. in U.S. Pat. No. 6,327,812 in which wood destroying insects, e.g., termites, are killed by applying a heated gas, such as heated air, to wooden surfaces or the like until the core of wooden structures is heated to a temperature typically about 120° F. to 135° F. Temperatures for killing other insects are said to be surprisingly close to this range. This method has been found to be very effective for killing termites. Another alternative to the toxic gas method is disclosed by James J. Chaudoin, et al. in U.S. Pat. No. 4,958,456, in which insects, e.g., roaches, fleas and beetles, are killed by a treatment of building spaces with boric acid and heat. However, the methods disclosed in the Forbes and Hedman et al. patents are quite complex in the preparation of the building. An enclosing tent structure must be formed around the structure to be decontaminated. Tenting the building with heavy tarpaulins requires workers to walk and arrange the tarpaulins on the roof, often damaging the roof system.
Also, these methods, using the described temperatures, is not effective for other organisms, such as bacteria, viruses, fungi, and molds such as, but not limited to, aspergillus oryzae, aspergillus terreus, aspergillus versicolor, cladosporium hergbarum, stachybotrys chartarum, penicillium aurantiogriseum, pencillium chrsogenum, pencillium gladrum and fusarium oxysporum. Further, many such fungi, molds and the like are a serious health hazard even when dead. Many people are allergic to the dust-like remains and residue, i.e., allergens, of these organisms that can also cause serious health problems. This is a particular problem to persons suffering from asthma, bronchitis, pneumoconious and other respiratory ailments, and is a common contributing factor to sick building syndrome (SBS).
It is also well-known that the heated air causes certain molds, fungi, etc. to sporulate, thus releasing spores into the structure and thus dispersing the harmful biological agents and possibly contaminating the structure to a greater degree than originally presented. The use of positive pressure within the structure, as described in Forbes and Hedman et al., further increase the likelihood that the biological contaminants will be dispersed throughout the structure. Forbes and Hedman et al. also disclose that the heated air can be vented from open windows and the like. However, when treating a contaminated building having harmful viruses, toxic molds, etc., it is not desirable to release such contagions into the air.
Volatile organic compounds (VOCs) have also been implicated as a possible cause of SBS. VOCs can originate from a variety of sources. Commercial examples include by-products of printing shop operations, office machine repairs, blueprint production, photographic processing and food service operations. In residences, such VOCs can include hobbyist products, cosmetics, perfumes, personal hygiene products, aerosol sprays, tobacco smoke, pet urine and even small emissions from the bodies of the occupants. Off gassing of VOCs is often a common by-product of various building/construction materials, for example paints, adhesives, plastics, carpeting, etc.
Such VOCs are implicated with SBS for mostly two reasons. First, the health effects from exposure to VOCs are consistent with SBS, ranging from irritant effects such as unpleasant odors and mucous membrane irritation, through general systemic effects such as fatigue, nausea, and difficulty concentrating. In addition, they may be of importance because some of them have been shown to have carcinogenic or adverse reproductive effects. Second, indoor concentrations of VOCs, particularly in new buildings, are often greatly elevated with respect to outdoor VOC concentrations. In fact, indoor VOC concentrations have typically been found to be two to ten times higher then outdoor concentrations, and indoor concentrations as much as 100 times higher than outdoor concentrations have been reported in new buildings.
Passenger occupiable vehicles, such as trains, buses, airplanes, etc. also include building/construction materials which are known to off gas VOC's. Also, the fuel, oil, and grease fumes and odors can infiltrate the passenger compartments of such vehicles and build-up within the seats, carpets, etc. over time. Due to the great number of people regularly traveling in such vehicles, there is an increased chance of coming into contact with contagious bacterium or viruses that can cause illness. Other organisms, such as fungi, and toxic molds can also be potentially found in such vehicles. As the company owning such vehicles necessarily must keep the vehicles running nearly constantly in order to realize the expected profit, such vehicles are rarely cleaned thoroughly. Even if the surfaces are superficially vacuumed and wiped down, there still remain live and dead organisms such as lice, mites, fungi, toxic molds, bacterium, viruses, VOCs, oxidized odors, and potentially insects which may have infested the vehicle, particularly those where food is prepared or served.
There are also instances when personal articles and small pieces of furniture need to be treated. For example, bedding and mattresses over time can accumulate a large amount of allergens, in the form of dust mites and their allergens, etc. Furniture may also experience water damage, causing fungi and toxic molds to grow thereon. These articles may also need to be treated for contagious bacterium or viruses that can cause illnesses.
Accordingly, there is a need for a system and method for killing and removing biological organisms and reducing odors and volatile organic compounds in enclosures such as commercial and residential buildings, boats, vehicles and portable containers. Such a method should be non-toxic and performed in a relatively short amount of time. Such a method should also effectively kill and remove a large proportion of the dead organisms and substantially reduce volatile organic compounds. The present invention fulfills these needs and provides other related advantages.